S. M. Sargand

Bio: S. M. Sargand is an academic researcher from Ohio University. The author has an hindex of 1, co-authored 1 publications receiving 167 citations.

Drape Prediction by Means of Finite-element Analysis

Abstract: The draping behaviour of fabric treated as an orthotropic shell membrane is predicted by using a geometric non-linear finite-element method, and the results are compared with actual behaviour. A drape tester employing photovoltaic cells was designed and constructed to determine the drape coefficient of fabric specimens of 10-in. diameter. The warp- and weft-direction tensile moduli of these samples were determined by using a Kawahata Tensile and Shear Tester, and literature values of Poisson's ratio were obtained. With this approach, excellent agreement between experimental and predicted drape coefficients resulted. For a 100% cotton plain-weave fabric, a drape coefficient of 68.4% was experimentally determined as compared with a predicted value of 71.0%.

Predicting the drape of woven cloth using interacting particles

Abstract: We demonstrate a physically-based technique for predicting the drape of a wide variety of woven fabrics. The approach exploits a theoretical model that explicitly represents the microstructure of woven cloth with interacting particles, rather than utilizing a continuum approximation. By testing a cloth sample in a Kawabata fabric testing device, we obtain data that is used to tune the model's energy functions, so that it reproduces the draping behavior of the original material. Photographs, comparing the drape of actual cloth with visualizations of simulation results, show that we are able to reliably model the unique large-scale draping characteristics of distinctly different fabric types.

A fast, flexible, particle-system model for cloth draping : CG in textiles and apparel

Abstract: Animating the drape of different cloths must address complex physical behaviors. This particle approach uses optimizations that make it faster than earlier implementations and allow it to simulate behavior over time.

A fast, flexible, particle-system model for cloth draping

Abstract: Animating the drape of different cloths must address complex physical behaviors. This particle approach uses optimizations that make it faster than earlier implementations and allow it to simulate behavior over time. The modeling system presented computes the full trajectories of particles and not just the final positions. This offers several important advantages. Since the full history of each particle is known, hysteresis effects can be modeled accurately. The Kawabata (1980) experimental data for different textiles can be input directly to the model. The effects of external forces, especially those produced by wind or moving solid bodies, can be modeled accurately. Despite this extra dimension of detail, our system computes final positions considerably faster than the times given by Breen, House and Wozny (1994). Our model can be easily extended to simulate the effects of manufacturing processes or interacting bodies. In particular, high stresses of the kind that occur in manufacturing can only be modeled if the full trajectory of each particle is known. We have implemented our model as a C++ class library. Particle systems are more flexible than approaches using continuum mechanics. Our system's fast computation times, mainly due to the numerical solution of ordinary differential equations, compare favorably to approaches using a finite-element method. Therefore, our approach might be an interesting alternative for other engineering problems currently solved by a finite-element method, for example, the computation of minimal surfaces, heavy membranes, vibrating membranes and population dynamics.

Computer graphics techniques for modeling cloth

Abstract: In this survey, we present a contemporary overview of cloth modeling techniques. 19 modeling techniques are summarized and categorized by their main theoretical method: geometrical, physical, or hybrid. The techniques within each category do not follow well-defined patterns. We therefore generally report each work independently according to the chronology of publication. At the end of the discussion of all techniques, we summarize their features in a table. We conclude by speculating on future research directions that could optimize the agreement between the requirements of visual realism and physical accuracy. The recommendations for future work consider the different goals in textile engineering and computer graphics.

A particle-based model for simulating the draping behavior of woven cloth

Abstract: This thesis presents a model of woven cloth that is capable of reproducing the draping behavior of a variety of fabrics. Here, draping behavior means the final draped configuration of a cloth, consisting of characteristic folds, over a solid object. The model utilizes a new approach, called particle-based modeling, to simulate the mechanical properties of complex materials. In contrast to continuum techniques, particle modeling is founded on the premise that by directly modeling the microstructures of a material and computationally aggregating their interactions correct macroscopic behavior will emerge. Cloth is not a continuous material, but rather a complex mechanism. Cloth's microstructure consists of threads interlaced in a particular weave pattern. Therefore, the model treats the thread crossing as the fundamental modeling unit, which is called a "particle". It is at the level of these particles that constraints are maintained, in the form of potential energy functions, on the relationships between the threads. The constraints maintained in the particle grid embody four basic mechanical interactions occurring in cloth at the thread level. They are thread collision, thread stretching, thread bending, and trellising. An important feature of the model is that its thread-relationship constraints can be defined to simulate specific types of woven materials. This is accomplished by deriving the model's energy functions from empirical mechanical data produced from a standard set of fabric measurement equipment, the Kawabata Evaluation System. Given this capability, a woven material may be measured on the Kawabata System, and a model with the material's mechanical properties may then be defined to confidently simulate its draping behavior on a computer. The validity of the model has been verified by performing two experiments with three different kinds of woven cloth. The first experiment recreates in simulation the standard measurement procedures that are applied to cloth and produces simulated mechanical data. The second experiment performs controlled draping experiments with real cloth, then recreates those experiments with draping simulations utilizing the model. This experiment demonstrates that the model is capable of reproducing the unique large-scale draping structures present in each of the experimental samples.